title: Embracing the irregular: a patient-specific image processing strategy for visual prostheses.
abstract: We propose a stimulation strategy for retinal prostheses that makes use of irregular shapes of elicited phosphenes. It is patient specific and thus relies on prior psychophysical measurements. Visual perceptions are stored in a phosphene map that relates stimulation parameters to the visual stimulus elicited. Based on this map, stimulation parameters are chosen in such a way that the edges of the target image are optimally represented through the shape of the phosphene. In a psychophysical pilot study, we compare this approach to one in which we choose phosphenes to match the brightness of the target image. We find that participants perform similarly well with both strategies overall. However, the results indicate that each strategy may have advantages for different stimulus sizes. Both of the proposed strategies are novel in using only previously recorded phosphenes rather than a model based on idealized assumptions about the relationship between stimulation parameters and phosphene properties.
authors.forename: Filiz Isabell
authors.initials: FI
authors.lastname: Kiral-Kornek
authors.forename: Craig O
authors.initials: CO
authors.lastname: Savage
authors.forename: Elma
authors.initials: E
authors.lastname: O'Sullivan-Greene
authors.forename: Anthony N
authors.initials: AN
authors.lastname: Burkitt
authors.forename: David B
authors.initials: DB
authors.lastname: Grayden
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D010719:Phosphenes; D010775:Photic Stimulation; D010865:Pilot Projects; D011601:Psychophysics; D014796:Visual Perception; D057488:Visual Prosthesis